1. Technical Field
The present disclosure relates to the fixation of orthopedic structures to bones. More particularly, the present disclosure relates to jigs used in conjunction with bone plates in minimally invasive surgery (MIS).
2. Brief Description of the Related Art
Bone plates are used in a variety of surgical procedures, such as to treat fractures of bones in the body. For example, an elongate bone plate with a plurality of fixation holes along its extent may be used to affix the bone plate to multiple bone fragments of a fractured bone. The bone plate bridges the gaps created between bone fragments, i.e., the fracture gaps, thereby providing support for the fractured bone and aiding in the healing process.
Insertion and affixation of a bone plate to a fractured bone may be accomplished with minimally invasive surgery (“MIS”). MIS methods of bone plate fixation can include making a small incision at or near an end of a fractured bone, so that only the end of the bone is exposed to the surgeon. A bone plate may then be inserted through the incision such that a bone contacting surface of the bone plate abuts the relevant bone fragments, with the length of the bone plate spanning at least a portion of the length of the fractured bone and bridging the fracture gap. Once the plate is properly positioned, the bone plate is affixed to the bone by passing fasteners through the skin, into fixation holes in the bone plate, and into the bone on both sides of the fracture gap. This MIS technique can include making stab incisions through the outer layer of skin to provide access for cannulas, which are inserted through the outer layer of skin to span the distance between the incisions and the bone plate fixation holes, so that each cannula corresponds to a respective hole position on the bone plate. A fastener may then be passed through each respective cannula to affix the bone plate to the bone.
An existing jig and method of use are shown in two brochures published by Zimmer, Inc, namely the “Zimmer® NCB® Plating System” brochure, copyright 2006, and the “NCB® Distal Femoral Plating System, Surgical Technique” brochure, copyright 2005, 2007 and 2008, the disclosures of which are hereby incorporated by reference herein in their entireties, and copies of which are filed in an Information Disclosure Statement on even date herewith. Similar surgical techniques are may also be used with the bone plate fixation system of the present disclosure.
FIGS. 1 and 2 are representative of jigs currently utilized. Referring generally to FIGS. 1 and 2, jig 12 may be provided to align cannulas (not shown) with respective fixation holes 16 on bone plate 10. Jig 12 may be attached to an end portion of plate 10 via fixation arm 20 so that, once plate 10 is positioned properly on a bone, cannulas may be passed through a plurality of holes 14 in jig 12 and advanced toward respective holes 16 in plate 10. Holes 14 in jig 12 are positioned and oriented to deliver fasteners to respective plate holes 16 in a desired trajectory. As best shown in FIG. 2, jig holes 14 may be laterally offset with respect to corresponding bone plate holes 16, so that respective axes of fasteners passed through the cannulas are directed toward the axis or center of the bone to which plate 10 is attached.
Jig 12 may be used with shorter bone plates by virtue of jig 12 being useable with plate 10, because the hole patterns of shorter bone plates relative to fixation arm 20 are contained within the hole pattern of plate 10. Referring again to FIG. 1, jig 12 may be used with shorter bone plates by using an appropriate number of jig holes 14 closest to fixation arm 20. Bone plate 10 has a generally straight or linear overall profile with fixation holes 16 that follow a consistent pattern across the body of plate 10, allowing the shorter bone plates to utilize the same jig holes 14 as the corresponding portion of bone plate 10. For example, when jig 12 is coupled with a short plate, only the jig holes 14 disposed between fixation arm 20 and short plate marker 22 are utilized. In bone plate 10, these jig holes 14 used with a short bone plate correspond with first set 30 of holes 16.
Similarly, jig holes 14 disposed between fixation arm 20 and middle marker 24 may be used for a medium length plate. These jig holes 14 correspond with both first set 30 and second set 32 of holes 16 in bone plate 10. For bone plate 10, jig holes 14 disposed between fixation arm 20 and long marker 26 (i.e., all of jig holes 14 on jig 12) may be used because bone plate 10 is a long length plate (as shown in FIGS. 1 and 2). These jig holes 14 correspond with first set 30, second set 32, and third set 34 of holes 16 in bone plate 10.